重载铁路钢桥结构安全性评估研究

发布时间：2018-07-08 15:49

本文选题：失效树 + 承载能力　；参考：《中国铁道科学研究院》2015年博士论文

【摘要】：近年来我国经济快速发展,铁路桥梁承受着越来越繁重的交通运能,通过增大列车轴重来增加运能、提高运输效率已成为目前铁路的发展趋势之一。而且,我国铁路货车制造技术已经接近或达到了世界先进水平,完全具备生产大轴重货车的能力。在这种情况下,我国既有铁路钢桥是否具备开行重载运输的条件,即在承载能力和疲劳性能等方面能否满足安全性要求,需要展开深入研究。另外,随着我国桥梁建造技术的不断进步,钢桥的跨度不断增大,结构构造在不断创新,大量新型构造细节也应运而生,新型构造细节的疲劳性能能否满足重载运输的要求,也需要加以关注。论文结合既有铁路钢桥开行重载列车后需要亟待解决的问题,从承载能力、疲劳加载特征以及疲劳寿命评估等方面出发,通过计算分析、关键构造细节疲劳试验等方式,从如下几方面展开了研究。采用失效树理论的最小荷载增量法,选择典型钢桁梁(64m下承式单、双线钢桁梁),对其在设计荷载、27吨、30吨轴重重载列车作用下的极限承载力进行计算分析。研究得到了在不同荷载加载条件下,钢桁梁的失效模式、失效控制杆件以及极限承载力,掌握了钢桁梁的安全储备。依据最不利换算均布荷载效应,通过挖掘动力系数的储备,对按照中-活载设计的桥梁对27吨、30吨轴重重载列车的适应性进行计算分析,得到了重载列车的适应跨度(影响线长度)范围。对不同疲劳寿命评估方法进行总结分析,包括基于S-N曲线的疲劳寿命评估方法和基于线弹性断裂力学的疲劳寿命评估方法,其中基于S-N曲线的疲劳寿命评估方法包括两种,一种是传统确定性的疲劳寿命评估法,一种是基于可靠性理论的疲劳寿命评估法。采用上述几种疲劳评估方法,选择典型钢桁梁(64m下承式单、双线钢桁梁),评估其运营30吨轴重重载列车后的疲劳寿命,得到了不同杆件的剩余疲劳寿命,及需要进行加固补强的杆件。对实桥加载波形进行研究分析,验证试验室加载波形与实桥加载波形的区别。选择铁路钢桥几种关键构造细节,开展了矩形波(梯形波)和正弦波两种波形加载条件下的疲劳试验研究。研究不同加载波形对于构造细节疲劳性能的影响程度,判断极端重载运输条件下,构造细节的疲劳性能是否有所改变,以及在进行疲劳检算时,其容许值是否需要折减和折减系数的取值。对各类新型钢桥构造细节进行分类总结,分别对主桁杆件构造细节、桥面系构造细节、主桁与桥面系连接等三大类17种构造细节进行归类分析,研究不同类型构造细节的重载适应性,对于疲劳强度不能满足重载运输条件的构造,提出相应的改进措施建议。
[Abstract]:In recent years, the rapid economic development of our country, the railway bridges bear more and more heavy traffic energy. By increasing the axle weight of the train, increasing the transport energy and improving the transport efficiency have become one of the developing trends of the railway. Moreover, the manufacturing technology of railway freight cars in our country is close to or reached the advanced level in the world, and it is fully equipped with large axle heavy cargo. In this case, in this case, whether or not the railway steel bridge has the condition of carrying heavy load, that is, whether it can meet the safety requirements in bearing capacity and fatigue performance, it is necessary to carry out a thorough study. In addition, with the continuous progress of the bridge construction technology in China, the span of the steel bridge is increasing, and the structure and structure are constantly innovating. A large number of new structural details have come into being. Can the fatigue performance of the new structural details meet the requirements of heavy haul transportation, and it also needs to be paid attention to. The paper combines the problems that need to be solved after the railway steel bridge opens the heavy haul train, which is based on the bearing capacity, fatigue loading characteristics and fatigue life assessment. Analysis of the key structural details fatigue test and other ways, from the following aspects, the minimum load increment method of failure tree theory is adopted to select the typical steel truss beam (64M down bearing single, double wire steel truss) to calculate and analyze its ultimate bearing capacity under the action of design load, 27 ton, 30 ton axle heavy load train. Under the same load loading condition, the failure mode, the failure control rod and the ultimate bearing capacity of the steel truss girder have mastered the safety reserve of the steel truss. According to the most unfavorable conversion average load effect, through the excavation of the dynamic coefficient, the adaptability of the 27 ton and 30 ton axle heavy load train according to the bridge of medium live load design is calculated and analyzed. According to the adaptation span (influence line length) range of the heavy load train, the different fatigue life assessment methods are summarized and analyzed, including the fatigue life assessment method based on the S-N curve and the fatigue life assessment method based on the linear elastic fracture mechanics. The fatigue life assessment method based on the S-N curve includes two kinds, one is the traditional determination. The fatigue life assessment method, one is based on the fatigue life assessment method based on the reliability theory, chooses the typical steel truss beam (64M down bearing single, double wire steel truss) to evaluate the fatigue life after the 30 ton axle heavy load train, and obtains the residual fatigue life of different rods, and the need to reinforce and supplement the fatigue life. This paper studies and analyzes the load waveform of the real bridge, and verifies the difference between the loading waveform of the test room and the actual bridge loading waveform. Select several key structural details of the railway steel bridge and carry out the fatigue test under the two loading conditions of the rectangular wave (trapezoid wave) and the sine wave. The different loading waveforms are studied for the structural details fatigue performance. The degree of influence is to determine whether the fatigue performance of the structural details is changed or not, and whether the allowable values of the structural details should be reduced and the reduction coefficient values are needed in the calculation of fatigue. The structural details of the new type steel bridges are classified, the details of the structural details of the bridge deck system, the main truss and the main truss are made respectively. 17 types of structural details are classified and analyzed in three major categories, such as bridge deck connection. The heavy load adaptability of different types of structural details is studied. Suggestions for improvement measures are proposed for the failure of fatigue strength to meet the heavy load transport conditions.
【学位授予单位】：中国铁道科学研究院
【学位级别】：博士
【学位授予年份】：2015
【分类号】：U446

【参考文献】